Science, asked by addiquee2nsaww, 1 year ago

24. Melting of wax is a physical change but burning of wax is a chemical change. Explain.

Answers

Answered by vasudha2
6
Melting of wax is a physical change but burning of wax is a chemical change.Melting is changing from the solid to the liquid state. Changes of state are physical changes.
The composition of the wax did not change and no new substance was formed.melting the wax doesn't change the chemical composition of the wax but when we burn wax the chemical composition of the wax changes.
A burning wax (candle)is an example of a chemical change because the paraffin wax, which is a hydrocarbon, undergoes a chemical reaction with oxygen to form water and carbon dioxide gas.
Answered by Amrit111Raj82
1

Question

The diameter of a semicircular table is 10 cm. Find the cost of polishing the semicircular table at the rate of ₹3.50 per sq.cm.

Answer

Diameter of a semicircular table = 10cm

Radius of the semicircular table

\begin{gathered} = (\frac{diameter}{2} ) \\ = ( \frac{10}{2} )cm \\ = 5cm\end{gathered}

=(

2

diameter

)

=(

2

10

)cm

=5cm

Area of the semicircular table

\begin{gathered} = (\frac{\pi {r}^{2} }{2}) \\ = ( \frac{22}{7} \times 5 \times 5 \times \frac{1}{2} ) {cm}^{2} \\ = 39.285 {cm}^{2} \end{gathered}

=(

2

πr

2

)

=(

7

22

×5×5×

2

1

)cm

2

=39.285cm

2

Cost of polishing the semicircular table at the rate of ₹3.50cm²

\begin{gathered} = ₹(39.285 \times 3.50) \\ = ₹137.4975\end{gathered}

=₹(39.285×3.50)

=₹137.4975

More Information

Surface Area of Cuboid = 2(lb+bh+lh)

Surface Area of Cube = 6(side)²

Area of four walls = 2(l+b)h

Lateral Surface Area of Cuboid = 2(l+b)h

Lateral Surface Area of Cube = 4(side)²

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